Field of the Invention
The present invention relates to a method useful for measurement of a position and orientation of an object of a known shape.
Description of the Related Art
In recent years, with increasing development of the computer vision, techniques that allow robots to perform complicated tasks are increasingly studied. Among the major examples of such tasks, there is the assembly of industrial products. When a robot autonomously performs an assembly work, an end effector, such as a hand, typically needs to hold the component (target object) to be assembled. Before holding the component, the robot captures an image of the actual environment by a camera. Then, by fitting model information of the target object to the captured image, the robot measures the position and orientation of the target object in the actual environment. Further, based on the obtained measurement result, the robot generates a movement plan and actually controls the actuator.
Further, the component to be assembled may have a complex shape and texture. Since robustness is required with respect to information fitting of model information to the actual environment for holding a component by a robot, various studies have been performed.
For example, Japanese Patent Application Laid-Open No. 2012-26974 discusses a method that assumes a position and orientation of a camera in a robust manner. According to this method, first, a plurality of initial positions and orientations is generated at a predetermined sampling interval in a possible range of the position and orientation of the camera. Then, the calculation of the fitting is performed for each initial position and orientation, and the position and orientation with the highest score is determined as the final position and orientation of the fitting.
However, the method discussed in Japanese Patent Application Laid-Open No. 2012-26974 is based on the assumption that the possible range of the position and orientation of the camera is determined in advance in an appropriate range. Thus, if this assumption is not satisfied, the position and orientation of the camera cannot be obtained in a robust manner.